Automated analyzers, including clinical biochemistry analyzers and other laboratory devices, have been conventionally used for many years. For example, automated clinical biochemistry analyzers are used to perform clinical testing on blood samples. These devices are required to produce results that are validated, and they must be calibrated, i.e., re-validated, on a regular basis.
Such analyzers have been calibrated using “standards” that are composed of the chemical substances present in test serums. However, the problems of accuracy of the calibration can arise, especially in terms of determining absolute values.
A method for improving the accuracy of the calibration can be accomplished by determining the differences between large numbers of test results using standards performed independently through blind studies conducted by several groups. Although this technique can be used universally, it is still inadequate for use as a method for confirming accuracy, because it is burdensome and time consuming.
In recent years, the certified accuracy of verification systems and devices has been determined by using analysis results obtained with a standard as true values based on a theoretical system for establishing the authenticity of world standards, and then determining accuracy by using trueness with respect thereto as a requirement for certification, and it is effective to realize validation techniques that coincide with these certification requirements.
In contrast, a validation technique has been previously proposed that improves calibration accuracy by reducing the effect of evaporation by dispensing an amount of liquid targeted for automated analysis (for example, 1 μl to 1000 μl) as determined according to a standard validation method from a liquid targeted for testing, and validating based on a dye method.
Validation techniques using dye methods consist of placing a prescribed amount of a reference solution containing a first dye component that absorbs light of a first wavelength in an absorbance detection container, measuring the optical absorbance of that wavelength component, placing a detection solution containing a second dye component that absorbs light of a second wavelength in the reference solution, and then measuring the optical absorbance of that wavelength component.
Since a comparison of the optical absorbance of the reference solution and the optical absorbance of the detection solution measured in this manner yields a value corresponding to the amount of the detection liquid, the amount of the detection liquid can be validated based on the amount of the reference liquid (based on the specifications of international standard—ISO8655—part 7).
Validation accuracy can be established for the elements used to determine accuracy of blood analysis results obtained by this dye method by firstly validating the light path length of the cell used for optical analyses, secondly validating the accuracy of dispensing of reaction reagents, thirdly validating the dispensing accuracy of biological specimens (blood), and fourthly validating incubation-temperature accuracy of the reaction layer.